How to get scaled the Wimp (system) Sprite? (

Hello,

I needs to put the small version (2x scaled down) of the Wimp sprite into the treeview control. For example me needs a small version of the “harddisc” sprite.
I tried to create own sprite in the own spritearea, capture the output to my sprite and paint the Wimp sprite using “OS_SpriteOp 52 – Paint Sprite Scaled”.
Problem that Wimp sprite has a mask and i can’t find a fast way how to copy scaled mask to my sprite.

Currently I using another capture operation to my sprite mask and paint the mask using “OS_SpriteOp 50 – Plot Mask Scale” but i get inverted mask. To correct it I must invert every mask pixel. It works but slow as require 2 SWI calls for every pixel.

May be another more fast way exists?

Here is my C++ code using TBX lib classes to manipulate the sprites.

tbx::Size sz, dst_sz;
tbx::SpriteArea mask_area;
int mode;
bool has_mask;
wimp_sprite->info(&sz, &mode, &has_mask);
dst_sz.height = sz.height / 2;
dst_sz.width = sz.width / 2;
// 0x301680B5 mode = true color 32bit sprite 90DPI
tbx::Sprite user_spr = _treeview_sprite_area.create_sprite_pixels(wimp_sprite->name(), dst_sz.width, dst_sz.height, 0x301680B5, 0, has_mask);
tbx::ScaleFactors sf;
wimp_sprite->get_wimp_scale(sf);
sf.ydiv(sf.ydiv() * 2);
sf.xdiv(sf.xdiv() * 2);
tbx::SpriteCapture capture_sprite(&user_spr, true, false);
wimp_sprite->plot_scaled(0, 0, &sf, 0, tbx::SPA_USE_MASK | (1 << 4));
capture_sprite.release();
if (has_mask) {
    // capture the mask
    tbx::SpriteCapture capture_mask(&user_spr, true, true);
    wimp_sprite->plot_mask_scaled(0, 0, &sf);
    capture_mask.release();
    // invert every mask pixel
    for(int y = 0; y < dst_sz.height; y++) {
        for(int x = 0; x < dst_sz.width; x++) {
            user_spr.mask_pixel(x, y, !user_spr.mask_pixel(x, y));
        }
    }
}

The Filer uses Wimp_PlotIcon. It looks like to call it you just need to fill out a block (wimp_icon in OSLib), there doesn’t need to be an ‘actual’ icon. And then flag wimp_ICON_HALF_SIZE = 0×800 should do the trick.

I can’t use Wimp_PlotIcon because I does not control the Treeview Toolbox control.
The Treeview control require sprite area and sprite name to display the icons and it always plot sprites in original size.
So I need to make own version of the scaled sprites from Wimp sprite area.

I see. What happens if you use Wimp_PlotIcon after redirecting to your sprite, instead of OS_SpriteOp 52?

What happens if you use Wimp_PlotIcon after redirecting to your sprite, instead of OS_SpriteOp 52

The SH manual says “If used outside the redraw/update loop, the graphic area will be reset to the current screen mode. This is not good if outputing to a sprite.” so I guess this might be a problem.

I’m a bit puzzled, does SpriteOp 52 (Put Sprite Scaled) not handle sprites with a mask correctly, if there’s a need to go through and invert the mask again aterwards?

@DavidS

Thank you very much. My problem was I tried to plot with R5 bit 3=1 (Use sprite mask/alpha channel).
Now I cleared bit 3 and use just R5=8 (with bit 4=1 – “Translation table can be ignored”), without bit 4 I get error “Bad translation table”.
I’m use for destination sprite the sprite mode word = 0×301680B5 – 32bit TBGR 90DPI
There is not even need to create separate mask, it seems use 8bit alpha as mask.
My code simplified to this:

tbx::UserSprite user_spr = _treeview_sprite_area.create_sprite_pixels(wimp_sprite->name(), dst_sz.width, dst_sz.height, 0x301680B5, 0, 0);
tbx::ScaleFactors sf(1,1,2,2);
tbx::SpriteCapture capture_sprite(&user_spr, true, false);
wimp_sprite->plot_scaled(0, 0, &sf, 0, (1 << 4));
capture_sprite.release();

In addition to previous comment.
This code works good for 16M true color 32bit sprites with 8bit alpha channel but not for 256 color or 16 color sprites with mask. When plot the 16/256 color sprite i got white or black background instead of transparent